The need for requesting emergency services is a common one in communication systems. Commonly-known, standard emergency numbers are helpful to eliminate caller confusion during emergency situations. When a user dials the standard emergency number (e.g., 911 in the United States), the telephone switch receiving the emergency call makes a decision as to where to route that call. In prior art terrestrial telephone systems, the routing decision is based on the location of the fixed instrument from which the call is made. This location may be determined from the phone number of the fixed instrument. After a call is routed to an emergency service center which handles the call, an emergency service center operator may be presented with the street address at which the fixed instrument is located. One problem with this system is that a user in an unfamiliar country may not know the proper standard emergency telephone number for that country. Further, the user may not speak the language of the operator.
In prior-an cellular systems, a subscriber unit user makes an emergency call request to an operator responsible for the area serviced by the cellular switch (i.e., a "service provider"). The operator must ask the caller to provide his or her location, and the call is then transferred to the proper emergency service center based on the given location.
Besides the drawbacks to fixed-station emergency response systems, a further drawback to this system is that the caller must provide location information which the caller may not know. Thus, a cellular system user traveling in an unfamiliar city or country is likely to have difficulty obtaining emergency services.
In a global satellite cellular communication system, other problems may arise. First, many areas of the world have no emergency response systems or governments may not be willing to pay the costs of emergency calls. A global cellular system user may need to resort to emergency services supplied by the service provider. Finally, a single switch may serve multiple continents, rendering an approach in which a single emergency service center handles all emergency calls unworkable.
What is needed is a method and apparatus for determining emergency call routing in a terrestrially-based or a satellite-based cellular communication system. Further needed is an emergency call routing method and apparatus in which a cellular subscriber does not need to provide location information in an unfamiliar language. What is further needed is a method and apparatus for determining emergency call routing in which the subscriber may use the standard emergency number for the subscriber's own country no matter where the subscriber is located.